In teaching useful information to, e.g., students and for various purposes it is well known that the employment of teaching aids or devices that hold the individual's attention, arouse their curiosity and provide an element of challenge to the person learning, gainfully motivate the individual to make the required application necessary to learn the intended useful information and retain same as part of their acquired knowledge. This is particularly true as it relates to teaching children fundamentals of useful information in, e.g., the mathematical disciplines a student must learn to be properly grounded in principles upon which higher levels of learning are founded.
It is desirable where such devices are used that they embody simplicity of construction, relative facility for use and also rely on application of certain logical step-by-step processes of thinking on the part of the user to achieve an intended end.